Place the cashews in a bowl and cover them with water. Soak for at least 1 hour. For preparation in advance, you can soak the cashews overnight, which is even better.
Drain the cashews. Add the cashews, 3/4 cup water, and 1/2 teaspoon kosher salt to a blender, then blend on high for 1 minute. Stop and scrape, then add additional liquid if necessary to come to a creamy consistency. Blend for several minutes until creamy and smooth.
Place 3/4 cup of the cashew cream into a medium bowl (a small amount will remain, which you can save for using as a vegan sour cream or mayo). Whisk in the apple cider vinegar, dried dill, garlic powder, onion powder, the remaining 1/4 teaspoon kosher salt, and 1/4 teaspoon black pepper.
You can serve right away, but we prefer refrigerating for a few hours so the flavors intensify and the texture sets up. Then before serving, mix it with a teaspoon or so of water to come to a drizzleable consistency.